> Of course, being a statstical measure, it doesn't tell at all which disk will
> fail next, so it can only be used for purchasing decisions and not for
> precautionary actions. See also the recent Google report on that topic.

Right.

However... an example. The chaps maintaining my car do some kind of
"preventive maintenance": they replace some pieces based on time and
kilometers. When I check those pieces, they seem ok, but... who knows, I
know they will not break on the road. Hopefully.

I'm curious.

On large installations such as those you and Kai mention, are SMART tests
useful to predict failure?